Wow, thank you for so many interesting answers !

I realized today that i don't really need something so evolved right now, and am in a 10 days rush. But it's an idea i'm interested in, so i will probably come back to it in the weeks /months to come.

I will probably go through your proposed solutions and write an overview of what the different methods say they do and don't do. Unless if someone did that before me : i can always hope !

If i realized that one of my naive ideas was worth some programming hours (but i guess one of your proposed solution will do better than me), i would probably produce something. Feel free to do it before my if you wanted to : i would be please to use the result =o)